1. Field of the Invention
This invention relates in general, to hydraulic couplings, and specifically to hydraulic couplings used in undersea drilling and production applications. More particularly, the invention involves a self-flushing hydraulic coupling for flushing bacteria and other contaminants from the hydraulic lines and other subsea equipment while both members of the coupling remain subsea.
2. Description of the Related Art
Subsea hydraulic couplings are old in the art. The couplings generally consist of a male and female member with sealed fluid passageways connecting therebetween. The female member generally is a cylindrical body with a relative large diameter longitudinal bore at one end and a relatively small diameter longitudinal bore at the other. The small bore facilitates connections to hydraulic lines, while the large bore seals and slidingly engages the male member of the coupling. The male member includes a cylindrical portion at one end having an outer diameter approximately equal to the diameter of the large bore in the female member of the coupling. The male member also includes a connection at its other end to facilitate connection to hydraulic lines. When the cylindrical portion of the male member is inserted into the large bore of the female member, according to various embodiments of the device, fluid flow is established between the male and female members.
The male member and female member are generally connected to opposing plates of a manifold and are held together by bolts or hydraulic members attached to the plates of the manifolds. The male member is commonly attached to one plate, while the female member is attached to an opposing plate so as to face the male member and align with it. The male member and female member may be attached to the manifold plates using various means, such as set screws or threads. Techniques for attaching the members to such manifold plates are well known to those skilled in the art.
A problem with most subsea hydraulic systems used in drilling and production operations utilizing water and soluble oil as hydraulic fluid, is the stagnation and growth of bacteria, as well as the accumulation of other contaminants, in the hydraulic lines and other subsea equipment. Periodically, the hydraulic lines must be flushed out to prevent the lines from stopping up. Typically, the flushing operation involves special flushing equipment that is sent subsea and utilized manually with divers, or, alternatively with a special diverless system. Both the automatic and manual system are very costly in terms of additional equipment needed and time lost during the flushing operation. Typically, it is desirable to flush out the hydraulic line connected to one member of the hydraulic coupling while that member is disconnected from the other member of the coupling. The biodegradable flushing fluid may be expelled from the disconnected coupling member into the sea water surrounding the coupling.